class Calc():
    def __init__(self):
        self.result = 0

    def jia(self, a):
        self.result = self.result + a

    def jian(self,a):
        self.result = self.result - 1

    def cheng(self,a):
        while True:
            pass
    def chu(self,a):
        self.result = self.result / a

    def get_result(self):
        return self.result

    def clear(self):
        self.result = 0